Rosemary, you have been through a lot. This is so hard.....
But here's my suggestion: change your definition of sex. I don't want to get too personal, and I don't know whether you have a partner, but you said penetration was impossible, which is not the same thing as saying that sex is impossible. Anything that feels good sexually is sex. So what you've lost is one kind of sex, but not all of sex -- just like you've lost some foods, but not all of eating. Explore other things that feel good or might feel good, maybe some you've never tried before....
Our culture is very strong on positing intercourse as the only kind of sex that counts, but sexuality is so much broader than that (and intercourse isn't what feels best for a whole lot of women who don't even have health issues).
Which is not to take away from what a huge loss this is...... and losses do need to be grieved.
My two cents.
48 years old, female.
2004 dx indeterminate colitis. Back and forth between Crohn's and UC dx. Many drugs, minimal success.
2010-11 Crazy skin and eye complications, high fevers, bad flaring. Out of good drug options, tired of scary drugs.
Feb 2011 -- proctocolectomy with permanent ileolostomy; abscess, blood clot. Still healing, still glad for the surgery